Drill-sharpening machine.



C. CHRISTIANSEN.

DRILL SHARPENING MACHINE.

APPLICATION FILED SEPT. 22, I915.

Patented Apr. 25,1916.

ormbn DRILL-SHARPENING MACHINE.

Specification of Letters Patent.

Patented Apr. 25, i916.

Application filed September 22, 1915.. Serial No. 52,069.

To all whom it may concern Be it known that 1, CHARLES CHRISTIAN- SEN, a citizen of the German Empire, resident at Gelsenkirchen, in the Kingdom of Prussia, German Empire, have invented new and useful Improvements in Drill-Sharpening Machines, of which the following is a specification.

The present invention relates to a drill sharpening machine, in particular for forging out the cutting edges of drills, for example of rock-drills, such as are used in mines.

In particular the present invention relates to such drill sharpening machines, in which the shank of the drill bears with its rear end against an anvil, and is dressed at its front end by a pneumatic hammer fitted with a matrix. In known drill sharpening machines of the aforesaid type the difficulty was experienced, that it was impossible to forge the cutting edges with clearance, so that the edge sharpened in the machine had to be undercut by a second operation either by hand or another machine, so that the final cutting edge should have both the required width and also the desired taper. The difliculty is obviated by the present invention and the sharpening, namely the forging of the face-surfaces of the cutting edge and the undercutting of the latter is performed in the same machine at one operation.

The present invention, for the said purpose, consists in that the forging die, in which the cutting edge of the drill is forged is not rigidly disposed, but is movable to a certain extent between the anvil and the pneumatic hammer.

In the accompanying drawing a constructional form of the invention is, exemplified.

Figure 1 is a general view bf the whole arrangement. Fig. 2 is a plan view, .on an enlarged scale, of the forging die elastically attached to the pneumatic hammer; the die being shown in an opened position; Fig. 3 is a side elevation of Fig. 2. Fig. 4t is a plan, corresponding to Fig. 2, but showing the die in closed position. Fig. '5 is a side elevation of Fig. 4. Fig. 6 shows the end of the drill, roughly forged out by hand. Fig. 7 is the same drill, with the cutting edge finished in the drill sharpening machine. Fig. 8 is the lower half of the forging die. Fig. 9 is the matrix for forging a drill edge according to Fig. 7 In Fig. 10 is shown in section on the line A-B in Fig. 3, the respective position of the matrix to the die, when the die is opened; in Fig. 11 is shown in section on the line C-D in Fig. 5, the respective position of the matrix to the die, when the die is closed. Fig. 12 is a section through the die and matrix on the line EF in Fig. 11. Fig. 13 shows the drill end forged out by hand, and Fig. 14: the drill end of a drill with a Z-shaped edge, finished in the machine.

In the drawing a is a bed-frame which is made of a length sufficient to cope with the longest drills. On this bed-frame the pneumatic hammer b is slidably disposed. At the one end of the bed-frame a is rigidly fitted an-anvil or abutment 0. The pneumatic hammer b is adjustable with the die (Z on the bed-frame a. This die at is, however, not rigidly attached to the pneumatic hammer b, but has only an elastic connection therewith. In the pneumatic hammer 7) long bolts 6 are secured, which extend through the die .and on which strong springs f are fitted, which bear with their lefthand ends against nuts screwed on said bolts 6, and with their right-handends against the die 12. The springs f, thus, tend to force the die d asfar as possible to the right. The die d is composed of the two exchangeable d1e-molds g and o of which the upper mold g is carried by a hinged lever h, which may be locked in closed position by aid of a locking lever i. To the lever 11. is fitted a laterally projecting pin 70. When the lever h is moved from the position shown in Figs. 4 and 5 into the position shown in Figs. 2 and 3, and the die is thereby opened, the pin 70 will move a wedge-shaped bolt Z between the pneumatic hammer b and the die (Z, the said bolt sliding with its beveled surface 1 on the beveled surface 03 of the die (Z and forcing the die 0Z aside, contrary to the action of the springs f. Thereby the distance between the pneumatic hammer b and the die at is enlarged. The drill may, therefore, be readily and easily placed with its roughly forged out end into the open die. hen the die is closed, the bolt Z may again recede, and the springs 7 force the die at as close up to the pneumatic hammer b as the shape of the rough forged ed e and the die molds g and 9 allow. After the drill has been, thus, placed with its right-hand, cutting end into the open die, the latter has been closedand the pneumatic hammer with p of the matrix m.

the die. and the drill has been moved so far to the" left that the left hand end of the drill bears against the anvil c, the pneumatic hammer is set into operation. The tool operated by the pneumatic hammer consists of the matrix m, against the rear end m of which the plunger of the hammer strikes in known manner, and the front end of which is hollowed out to the shape, the cutting edge is to receive. By the blows of the hammer on the matrix m the latter is driven to the left with the die cl 'against the springs 7 which force the die (l and the matrix back toward the right. By the reciprocating Strokes of the die the cutting edge is simultaneously forged and cleared at the back, so that the'cutting edge receives the desired shape both on its face and at its back, and also the required, exact width, at one single operation. After the loekinglever c' hasbeen "opened, and'the lever 'h' has been raised, the drill is readily removed from the die. Preferably the matrix m and the "die d are coupled by guides in such a manner, that only 'a relative longitudinal displacement, but no rotation-is possible. For securing this object the matrixis guided in bothhalves of the dieby fiat keys 0 and 0 embedded in the two die halves g and 9 respectively, both in the cylindrical and the conical part, which keyfs'engage corresponding flat faces In the drill sharpening machine constructed according to the present invention, therefore, the die is, during the forging operation, not rigidly attached to either the pneumatic hammer or the-frame of themachine, and is .reciprocated violently under action of the blows of the hammer and the pressure of the edge being upset, Bypslueh means a good and perfect clearing of the cutting edge is obtained.

I claim:

1. In a drill sharpening machine, means for, holding the drill, a pneumatically actuated matrix adapted to engage the cutting end of the drill, a yieldingly mounted forging-die inclosing said end movable in one direction by. the matrix, and means tomove said die against. the action of the matrix.

2. In a drill sharpening machine, a fixed abutment for one end of the drill, a spring 'urged forging-die adapted to receive the cutting end ofthe latter, and a pneumatically actuated matrix adapted to form the cutting edge of the drill and engage the die to reciprocate the latter to forge the clearance to the cutting edge of the drill. .3. In a drillsharpening machine, a supporting bed, an anvil fixed on one end thereof, a pneumatic hammer adjustably mount.

ed'on-the bed, bolts extending from the hammer, a forging-die inclosing the cutting end of the drill slidably mounted on the bolts, springs on the latter to press the die toward the hammer, and a matrix actuated by the latter adapted to engage the drill and move the die against the action of the springs.

t. In a drill sharpening machine, a supporting bed, an anvil fixed on one end there of, a pneumatic hammer adjustably mounted on the bed, a. forging die comprising two pivotally connected mold sections yieldingly connected with the hammer, and normally held against the latter, a wedge-shaped bolt interposed between the die and hannner, and means operated by the movement of one of the sections to automatically actuate said bolt to separate the die and hammer.

5. In a drill sharpening machine, a supporting bed, an anvil fixed on one end thereof, a pneumatic hammer adjustably mounted on the bed, a forging die carried by the. hammer inclosing the cutting end of the drill, means to yieldingly press said die toward said hammer, a matrix actuated by the latter adapted to form the cutting edge on the drill and move the die against said pressing means, thereby reciprocating the die to form a clearance to the cutting edge, and means to prevent rotation of the matrix relatively to the die.

6. In a drill sharpening machine, a supporting bed, an anvil fixed on one end thereof, a pneumatic hammer adjustably mounted on the bed, a forging die carried by the hammer inclosing the cutting end of the drill, means to yieldingly press said die toward said hammer, a matrix actuated by the latter adapted to form the cutting edge on the drill and move the die against said pressing means, thereby reciprocating the die to form a clearance to the cutting edge, fiat keys mounted in the die adapted to engage corresponding faces on the matrix to prevent rotation of the latter relatively to the die.

7. In a. drill sharpening machine, a supporting bed, an anvil fixed on one end there of, a pneumatic hammer adjustably mounted on the bed, a forging die comprising two pivotally coqnected mold sections yieldingly connected with the hammer, and normally held against the latter, a wedge-shaped bolt interposed between the die and hammer, and a laterally projecting pin on one of said mold sections adapted to engage the bolt on opening the die to move said bolt to separate the die and hammer.

In witness whereof I have hereunto set my hand in presence of two witnesses.

CHARLES CHRISTIANSEN.

Vitnesses J. D. Zinsnnnr, G. L. KAEMPnns.

copies of this patent may be obtained for five cents each, by addressing the Commissioner of l'atentn, Washington, D. G. 

